The present invention relates to an apparatus for detecting moving bodies, and more particularly to an apparatus for detecting a moving body, measuring the speed of the body and discriminating the shape of the body by picking up the moving body with a television camera and processing the video signals delivered from the camera.
Such moving body detecting apparatus include those using a spatial filter. The spatial filter is disposed in the image forming plane of an objective lens or reflecting mirror, inhibits the influence of the irradiation of light from the background other than an object and included in the field of view of an optical system and is used effectively for detecting the object with improved ability and for measuring the speed of the object. More specifically the spatial filter comprises a reticle or grating arranged in the image forming plane of the optical system, or a photoelectric transducer per se which is composed of a large number of photoelectric elements arranged in parallel with one another. Reticles or gratings further include a photoelectric reticle comprising opaque portions and transparent portions which are arranged alternately and controlled to move in one direction in this arrangement. With such a reticle or an array of photoelectric elements, however, the component elements are arranged at a definite spacing, so that the spatial frequency is fixed to a value determined by the spacing. The system is therefore capable of detecting only a specific frequency component of the object and is not usable universally.